| 摘要 |
PROBLEM TO BE SOLVED: To prevent generation of a surface defect due to that the material is lapped inside a fillet part, in intermediate rolling, by forming a relief part on the whole periphery of a radius part side face of a horizontal roll of a rough universal mill and rolling so that a roll gap reducing quantity per one pass of a vertical roll is set smaller than a relief quantity of the horizontal roll. SOLUTION: A large wide flange shape steel is produced a rough rolling process using a breakdown mill, an intermediate rolling process using a rough universal mill/edging mill and a finish rolling process using a finish universal mill. A horizontal roll 31 has a relief part 31a on the whole periphery of an radius part side face. A relief quantity (dx) of the relief part 31 is preferably <=15 mm. A roll gap reduction quantity X of a vertical roll 32 is made smaller than a relief quantity (dx) per one pass. Further, the distance from a roll face in the direction orthogonal to the roll axis at a start point of the relief part 31a at a roll side face is preferably more than ten times of the relief quantity (dx). |
